Flow Cytometry: a versatile tool for stem cell research

Stem cell identification and characterization from a heterogeneous cell population relies on analysis of expression of specific markers either on the cell surface or inside the cell. Analyses of these markers' expression are often done using bulk techniques such as qRT-PCR, microarray, and Western blotting. Although immunofluorescence enables protein marker expression analysis in single cells, it is largely a qualitative technique. Flow cytometry can extend such analyses up to single-cell resolution. In addition, it offers rapid, high-throughput, simultaneous quantification of other parameters, such as the proliferative capacity of cells. Moreover, fluorescence-activated cell sorting (FACS) can physically isolate even rare populations of stem cells from a heterogeneous sample. This review discusses the scope of flow cytometry in the identification and characterization of various types of stem cells. Also, it highlights recent advances and specific approaches in the field for studies focused on stem cells.